The Patient Self-Determination Act (PSDA) has focused national attention on advance directives as one means for a patient to ensure adherence to his or her treatment preferences in the event of future incompetence due to illness or injury. Conceptual arguments have supported policies encouraging advance directives. Yet, little empirical research has been done to address the impact of advance directives on medical care. Can advance directives be incorporated into routine practice in such a way that directives are valid and effective? There is now a clear and pressing need for definitive, focused and generalizable research. We propose an invitational working conference to review current knowledge about advance directives; to consider methodologic issues in research about advance directives and to articulate research priorities relevant to shaping policy. Conference invitees will be those people who have been strong and consistent leaders in research as well as a few leading theorists from law and philosophy. In addition to education of an networking among the participants, the conference will result in a series of overview papers summarizing the status of research in the field and a "white paper" from the participants outlining the priorities for future research to guide policy in regard to advance directives and health care decision-making for incompetent adults.